Transparent Housing Geometry for Stray Light Control in Powder Sensors
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Solution Overview
Problem
Conventional powder sensing devices using light transmission-type sensors face issues with stray light interference, leading to inaccurate detection of powder presence due to thickened housing portions, and require complex configurations to prevent erroneous sensing.
Innovation Solution
A powder sensing device with a housing formed of a transparent member, featuring a light transmission-type sensor where the housing is positioned between the light emitting and receiving units, with strategically designed surfaces that extend away from the optical axis to minimize stray light interference, allowing for accurate powder detection in a simple configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light transmission-type sensor is used to sense powder presence in a housing, then the sensing function is achieved, but stray light from thickened housing portions causes erroneous detection
Solution Approach 1:
The patent extracts the harmful stray light paths from the optical system by designing the housing surfaces to redirect light away from the light receiving unit. Specifically, the light incident surface and light emission surface are configured with specific orientations to prevent stray light generated at thickened portions from reaching the sensor, thereby separating the useful light path from harmful stray light paths.
Solution Approach 2:
The patent applies local quality by configuring different surfaces of the housing with different orientations and properties. The light incident surface and light emission surface are specifically designed with angles that optimize light transmission while minimizing stray light. The adjacent surface extending away from the optical axis provides localized light blocking where needed without affecting the overall sensing function.
2Object-affected harmful factors
If additional light shielding members are added to prevent stray light, then stray light interference is reduced, but the device configuration becomes complex
Solution Approach 1:
The patent merges the light shielding function with the housing structure itself. Instead of adding separate light shielding members, the housing's light incident surface, light emission surface, and adjacent surface are configured to perform both structural containment and stray light prevention functions simultaneously. This integration eliminates additional components while maintaining sensing accuracy.
Solution Approach 2:
The housing structure is designed to serve multiple functions: containing the powder, providing optical paths for light transmission, and preventing stray light interference. The surfaces of the housing are configured to redirect light appropriately, making the housing itself a multi-functional component that eliminates the need for dedicated light shielding elements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents stray light from reaching the light receiving unit, ensuring stable and accurate sensing of powder presence without the need for additional light shielding members, thus maintaining a simple and efficient design.
Implementation Method 1
a light emitting unit configured to emit light
Implementation Method 2
a light receiving unit configured to receive light emitted from the light emitting unit
Implementation Method 3
The adjacent surface extends so as to be farther away from an optical axis that connects the light emitting unit and the light receiving unit as the adjacent surface is closer to the light emission surface
Data Source
AI summary
A powder sensing device includes: a housing formed of a transparent member and having powder housed therein; and a light transmission-type sensor capable of sensing that powder is housed in the housing, the light transmission-type sensor including a light emitting unit and a light receiving unit, the light transmission-type sensor being provided such that at least a part of the housing is disposed between the light emitting unit and the light receiving unit. The housing has a light incident surface, a light emission surface and an adjacent surface provided adjacent to the light emission surface. The adjacent surface extends so as to be farther away from an optical axis that connects the light emitting unit and the light receiving unit as the adjacent surface is closer to the light emission surface in a direction of the optical axis that connects the light emitting unit and the light receiving unit.